I wish to thank all of you for your comments.
In fact, the solutions you proposed mostly coincided with mine
(including the one using type families) but, in my opinion, they are
more cumbersome than the prefixed names solution.
Going back to my example:
f x = open $ open x
where:
data Foo = {
Wow, that's kind of cute:
{-# LANGUAGE UnicodeSyntax #-}
(＊) = (*)
(／) = (/)
公式 高 中 低=高＊中＊低／整數
整數 = 123
Oddly, if I change the order of these definitions I get syntax errors.
Very mysterious. Nice how it knows that ＊ is a symbol, but I'm not
sure how I'm supposed to name a type. It certainly
Excerpts from Jinjing Wang's message of Thu Jan 14 01:28:31 +0100 2010:
| The hyena backend is essentially just a translator between hack and
| wai, i failed to finished it since I can't understand iteratee
| (seriously) and eventually got distracted ...
If I have well understood you miss a
Hi Michael,
no, the message was not meant to be off-list, that was just me
pressing the wrong button :-)
Regarding happstack, I do not believe that there is a contrast with
your effort, the core of happstack is in its persistency mechanism not
in its http interface so I think it would be great
2010/1/14 Evan Laforge qdun...@gmail.com:
Wow, that's kind of cute:
{-# LANGUAGE UnicodeSyntax #-}
(＊) = (*)
(／) = (/)
公式 高 中 低 = 高 ＊ 中 ＊ 低 ／ 整數
整數 = 123
That code snippet is also perfectly legal Haskell without the
UnicodeSyntax language extension. You use UnicodeSyntax if you want to
2010/1/14 Jinjing Wang nfjinj...@gmail.com
Hyena is especially tuned for streaming and that's exactly what hack
can't do (in practice).
Isn't possible to stream an (almost) infinite bytestring trough hack?. I
ever trough that the laziness of haskell is a great advantage in Web
applications.
On Thu, Jan 14, 2010 at 12:50 PM, Alberto G. Corona agocor...@gmail.comwrote:
2010/1/14 Jinjing Wang nfjinj...@gmail.com
Hyena is especially tuned for streaming and that's exactly what hack
can't do (in practice).
Isn't possible to stream an (almost) infinite bytestring trough hack?. I
Am Donnerstag 14 Januar 2010 08:25:48 schrieb Will Ness:
Daniel Fischer daniel.is.fischer at web.de writes:
Am Mittwoch 13 Januar 2010 10:43:42 schrieb Heinrich Apfelmus:
I wonder whether it's really the liveness of pair in
mergeSP (a,b) pair
= let sm = spMerge b (fst pair)
I still get the undefined reference errors.
It is likely there is some combination of other mistakes as well
then. Other responses have made suggestions of fixes you require in
the C++ code for instance. You will need those as well.
I did eventually get ghc to compile
Main.hs by
Am Donnerstag 14 Januar 2010 11:38:57 schrieb Roel van Dijk:
I was a bit surprised that you could use ＊ as an operator since it is
a punctuation character. Maybe there are some corner cases with
fullwidth characters or with composition of characters.
Thus speaketh the report
2010/1/14 Michael Snoyman mich...@snoyman.com
Well, for one thing, you'd need to use lazy IO to achieve your goal, which
has some safety issues. As things get more and more complex, the
requirements of lazy IO will continue to grow. This also has implications
for number of open file handles
On Thu, Jan 14, 2010 at 1:20 PM, Alberto G. Corona agocor...@gmail.comwrote:
2010/1/14 Michael Snoyman mich...@snoyman.com
Well, for one thing, you'd need to use lazy IO to achieve your goal, which
has some safety issues. As things get more and more complex, the
requirements of lazy IO
Thus speaketh the report (http://haskell.org/onlinereport/lexemes.html):
symbol - ascSymbol | uniSymbolspecial | _ | : | | '
ascSymbol - ! | # | $ | % | | * | + | . | / | | = | | ? | @
| \ | ^ | | | - | ~
uniSymbol - any Unicode symbol or
Roel == Roel van Dijk vandijk.r...@gmail.com writes:
Roel I think it is time for an Obfuscated Haskell Contest :-)
Are you allowed to use obsolete scripts for your identifiers? :-)
--
Colin Adams
Preston Lancashire
___
Haskell-Cafe mailing list
On Thu, Jan 14, 2010 at 12:47 PM, Colin Paul Adams
co...@colina.demon.co.uk wrote:
Roel == Roel van Dijk vandijk.r...@gmail.com writes:
Roel I think it is time for an Obfuscated Haskell Contest :-)
Are you allowed to use obsolete scripts for your identifiers? :-)
Sure, I'll consider bonus
Magnus Therning mag...@therning.org writes:
Seriously, cmdargs is *brilliant*. It's also magic (to me).
On this list, I'm uncertain whether brilliant is a warning or a
recommendation, but magic is clearly irresistible, so I had a go at
using cmdargs.
And I agree, it is really nice in quickly
On Thu, Jan 14, 2010 at 1:58 PM, Alberto G. Corona agocor...@gmail.comwrote:
2010/1/14 Michael Snoyman mich...@snoyman.com
On Thu, Jan 14, 2010 at 1:20 PM, Alberto G. Corona
agocor...@gmail.comwrote:
2010/1/14 Michael Snoyman mich...@snoyman.com
Well, for one thing, you'd need to
Hello,
I have just released hakyll[1] 1.0. It is now available on hackage[2].
This is considered a first stable release (hence 1.0), and pretty it
is functional.
Hakyll is a Haskell library for generating static sites. It is written
in a very configurable way and uses an xmonad-like DSL for
Niklas Broberg wrote:
Haskell '98 apparently features 25 reserved words. (Not counting forall
and mdo and so on, which AFAIK are not in Haskell '98.)
21 actually. case, class, data, default, deriving, do, else, if,
import, in, infix, infixl, infixr, instance, let, module, newtype, of,
then,
Can someone give an example of a reasonable function that never uses one
of its parameters, and justify the existence of that parameter in this case,
please?
Because for this example,
f :: _unused - A - B
f _ a = b
I think what I'd do is to write the function f without that first parameter,
and
Ozgur Akgun ozgurak...@gmail.com writes:
Can someone give an example of a reasonable function that never uses one
of its parameters, and justify the existence of that parameter in this case,
please?
I would like to bring your attention to the const function:
,
| const :: a - b - a
|
Ozgur Akgun ozgurak...@gmail.com writes:
Can someone give an example of a reasonable function that never uses one
of its parameters, and justify the existence of that parameter in this case,
please?
E.g, 'const' is useful when you need something to feed to a higher order
function:
-- an
Hello,
I realized today that the type for deleteBy in Data.List is too restrictive.
The code is:
deleteBy:: (a - a - Bool) - a - [a] - [a]
deleteBy _ _ []= []
deleteBy eq x (y:ys)= if x `eq` y then ys else y : deleteBy eq x ys
though the type deleteBy :: (b - a -
Hi,
First of all, sorry if its in the wrong section..
But I'm just having trouble getting to grips with Haskell. I have my
functional programming exam tommorow and I'm struggling to understand any of
this.
We worked through the book The Craft Of Functional Programming and Im trying
to work my
Since you can define operators in Haskell, would it make sense to include
'=', '--', ':', ',' etc. as reserved names since those can't be used as
operator names?
They are indeed reserved operators in the report. 11 of those:
.. : :: = \ | - - @ ~ =
To be fair, _ is also a reserved
On Thu, Jan 14, 2010 at 12:45 AM, Colin Paul Adams
co...@colina.demon.co.uk wrote:
Tom == Tom Tobin korp...@korpios.com writes:
Tom readability. The ASCII characters are universal and easily
Tom recognized
No they are not.
My wife is Chinese. When she was learning pinyin as a child,
But after that im lost :(
Is there any general advice? Just keep reading the book till it drills into
my big head?
Is it that you're having difficulty knowing how you'd solve certain classes of
problems using Haskell? You're stuck in an imperative rut?
The O'Reilly book Real World
Hi,
it may be a bit too late for you, but in general working through
Smullyan's To Mock a Mockingbird
(http://en.wikipedia.org/wiki/To_Mock_a_Mockingbird) may help in
coming to grips with some of the theory (and intuition) behind
functional programming.
The Real World Haskell book is also a good
Pretty much yeah.. Im going through the book and things like :
Define a function rangeProduct which when given natural numbers m and n,
returns the product m*(m+1)**(n-1)*n
I got the solution from my lecture notes but I still dont understand it..
rangeProduct :: Int - Int - Int
It may be a bit late but I'll try anything
Thankyou, I'll have a read :-)
Matthias Görgens-2 wrote:
Hi,
it may be a bit too late for you, but in general working through
Smullyan's To Mock a Mockingbird
(http://en.wikipedia.org/wiki/To_Mock_a_Mockingbird) may help in
coming to grips
On Thu, Jan 14, 2010 at 7:52 AM, Ian675 adam_khan_...@hotmail.com wrote:
Is there any general advice? Just keep reading the book till it drills into
my big head?
Also don't be afraid to ask specific questions on the Beginners
mailing list; while Cafe is a good general resource, Beginners is
All Lisps have special forms which are evaluated uniquely and differently
from function application and are therefore reserved words by another name.
For example, Clojure has def, if, do, let, var, quote, fn, loop, recur,
throw, try, monitor-enter, monitor-exit, dot, new and set!.
Yes, but
On 14 Jan 2010, at 14:42, Matthias Görgens wrote:
All Lisps have special forms which are evaluated uniquely and differently
from function application and are therefore reserved words by another name.
For example, Clojure has def, if, do, let, var, quote, fn, loop, recur,
throw, try,
Ketil Malde ke...@malde.org writes:
- CmdArgs helpfully provides default --help, --version as well as
--quite and --verbose. For the two former, there's also a nice
default implementation, but presumably the latter two are for use in
the program proper. Unfortunately, I don't know how
Maciej Piechotka schrieb:
Hmm. May I ask how to do for example something depending on POSIX or
WinAPI? I am sorry but I cannot see how any of the above problems could
be solved.
Sure, I choose different Hs-Source-Dirs for the different platforms.
Multiple Hs-Source-Dirs are merged.
On Thu, 14 Jan 2010 14:42:06 +, you wrote:
All Lisps have special forms which are evaluated uniquely and differently
from function application and are therefore reserved words by another name.
For example, Clojure has def, if, do, let, var, quote, fn, loop, recur,
throw, try,
Haskell has dropped out of the top 50 at Tiobe [1]; how could this hapen?
Let's start selling mobile phones that can only be programmed in Haskell
:-)
[1] http://www.tiobe.com/content/paperinfo/tpci/index.html
--
Met vriendelijke groet,
Henk-Jan van Tuyl
--
http://Van.Tuyl.eu/
2010/1/14 Henk-Jan van Tuyl hjgt...@chello.nl:
Haskell has dropped out of the top 50 at Tiobe [1]; how could this hapen?
Let's start selling mobile phones that can only be programmed in Haskell :-)
[1] http://www.tiobe.com/content/paperinfo/tpci/index.html
--
Met vriendelijke groet,
Hello,
Happstack is currently bundled with it's own lazy I/O based HTTP
backend. Ideally, we would like to split that out, and allow happstack
to be used with that backend, hyena, or other options.
A primary using for using hyena would be for the benefits of
predictability and constant
OK. Before anyone expends any e-ink replying to my reply below -- the one
where I
demonstrate that I don't understand what -c, -cpp mean to 'ghc' (not that
you can
blame me, since there isn't any documentation in the 'ghc' man page) -- I
see why
the Main.o file doesn't run. It's an object file,
On Thu, 14 Jan 2010 15:38:26 +0100, Ian675 adam_khan_...@hotmail.com
wrote:
Pretty much yeah.. Im going through the book and things like :
Define a function rangeProduct which when given natural numbers m and n,
returns the product m*(m+1)**(n-1)*n
I got the solution from my lecture
Hello
Does you find this version easier to understand?
rangeProduct :: Int - Int - Int
rangeProduct m n = if m n then 0
else if m == n then m
else m * rangeProduct (m+1) n
I would suspect the main point of the example is
On Thu, Jan 14, 2010 at 5:42 PM, Jeremy Shaw jer...@n-heptane.com wrote:
Hello,
Happstack is currently bundled with it's own lazy I/O based HTTP backend.
Ideally, we would like to split that out, and allow happstack to be used
with that backend, hyena, or other options.
A primary using for
Unicode identifiers are fun but this is a good point. The line has
to be somewhere, so it might as well be in the historical position
unless there are widely agreed on benefits to moving it.
I have already crossed that line:
Ha, well haskell programmers wouldn't be haskell programmers if
thankyou.. that made more sense to me :)
What im doing now is..
Im still working through the Craft of Functional Programming book but I've
found a site that has solutions to some of the excercise questions. So i'm
noting them down and trying to make sense of them
Is that a good approach?
Hi All,
I was just going over the paper titled - Standard ML as a meta programming
language by Samuel Kamin - It has a few ideas of generating C++ code from ML.
The first one being generating C++ top down parser. I wanted to try out the
sample in Haskell - I was wondering if anyone's already
2010/01/07 Maciej Piechotka uzytkown...@gmail.com:
On Thu, 2010-01-07 at 13:32 +0100, Johannes Waldmann wrote:
Dear all,
It's not exactly Haskell-specific, but ...
I am trying to track down the origin of the proverb
the existence (or: need for) a preprocessor
shows omissions in (the
Hi Sebastian,
You might also want to look at how xmonad handles it's configuration.
Basically the configuration file is the main-file that produces the
executable and takes in the rest of xmonad as a library. This works
out quite well, but you need a compiler to update the configuration.
Hi
The CmdArgs manual might help:
http://community.haskell.org/~ndm/darcs/cmdargs/cmdargs.htm
Seriously, cmdargs is *brilliant*. It's also magic (to me).
On this list, I'm uncertain whether brilliant is a warning or a
recommendation, but magic is clearly irresistible, so I had a go at
Yes. An approach that I have always used that has worked well for me is to
keep a list of tricks while I am studying. Whenever I get stuck on a
practice problem but eventually figure it out (either by simply thinking
harder, looking it up, or asking someone for help), I try to identify the
On Fri, 25 Dec 2009, Lennart Augustsson wrote:
sizeOfPtr :: Ptr a - Int
sizeOfPtr = sizeOf . (undefined :: Ptr a - a)
No need for scoped type variables. But it does assume sizeOf does not
use its argument.
That's even better. I'll add that to the Wiki.
On Thu, Jan 14, 2010 at 5:19 AM, Ozgur Akgun ozgurak...@gmail.com wrote:
Can someone give an example of a reasonable function that never uses one
of its parameters, and justify the existence of that parameter in this case,
please?
As I mentioned, this is not only about parameters, but about
Hello Kashyap
I can do MSL and Region, maybe I did the parser combinators but I
can't find them at the moment.
I tried to keep the code close to the original SML, so as Haskell code
its not pretty. Not having quasiquote was a problem.
Best wishes
Stephen
Martijn van Steenbergen wrote:
Niklas Broberg wrote:
21 actually. case, class, data, default, deriving, do, else, if,
import, in, infix, infixl, infixr, instance, let, module, newtype, of,
then, type, where. There's also three special words that can still be
used as identifiers, so aren't
Which is weird, because 'srilm.o'/'srilm.h' are the files that define the
mysterious undefined references. I'll keep plugging away and report
back when (or whether) I make some progress. In the meanwhile, if anyone
has a clue, I'm all ears.
Best,
D.N.
Malcolm Wallace wrote:
However, if
On Jan 14, 2010, at 8:38 PM, Andrew Coppin wrote:
Martijn van Steenbergen wrote:
Niklas Broberg wrote:
21 actually. case, class, data, default, deriving, do, else, if,
import, in, infix, infixl, infixr, instance, let, module, newtype,
of,
then, type, where. There's also three special words
Am Donnerstag 14 Januar 2010 20:42:42 schrieb DNM:
Which is weird, because 'srilm.o'/'srilm.h' are the files that define
the mysterious undefined references. I'll keep plugging away and
report back when (or whether) I make some progress. In the meanwhile,
if anyone has a clue, I'm all ears.
On Thu, Jan 14, 2010 at 2:08 PM, Daniel Fischer
daniel.is.fisc...@web.de wrote:
Just an idea. Are you on windows?
If so, then your foreign calls would probably have to be
foreign import stdcall srilm.h whatever ...
instead of
foreign import ccall ...
Yes, I came here to say that too. I
Hello Daniel
On Windows, isn't stdcall vs ccall still dependent on the actual
library and what compiled it - commonly MSVC (stdcall) or gcc (ccall)
of course?
I could very easily be wrong...
Best wishes
Stephen
2010/1/14 Daniel Fischer daniel.is.fisc...@web.de:
Am Donnerstag 14 Januar
Hello Daniel,
Thursday, January 14, 2010, 11:08:24 PM, you wrote:
i think you are wrong. stdcall used for std windows dlls, but gcc by
default generates ccall things. and cl anyway useless here
Just an idea. Are you on windows?
If so, then your foreign calls would probably have to be
Nope. Ubuntu Linux (Intrepid Ibex). I wish it were that simple.
--D.N.
Daniel Fischer-4 wrote:
Am Donnerstag 14 Januar 2010 20:42:42 schrieb DNM:
Which is weird, because 'srilm.o'/'srilm.h' are the files that define
the mysterious undefined references. I'll keep plugging away and
Hello DNM,
Thursday, January 14, 2010, 10:42:42 PM, you wrote:
there is better way rather than playing with random bits. just find
tutorial on FFI, and try it. once this example works, start modifying
it to learn various aspects of ffi and add functionality you need
it's one thing i've learned
Am Donnerstag 14 Januar 2010 21:39:57 schrieb DNM:
Nope. Ubuntu Linux (Intrepid Ibex). I wish it were that simple.
--D.N.
Okay, so it's not a borken OS 8-)
Can you post ought to be compiling code?
That might help locate the problem.
___
2010/1/14 Bulat Ziganshin bulat.zigans...@gmail.com:
there is better way rather than playing with random bits. just find
tutorial on FFI, and try it. once this example works, start modifying
it to learn various aspects of ffi and add functionality you need
Also binding to a C library is
I am pleased to announce the Functional Programming Bibliography
at http://www.catamorphism.net/
The functional programming bibliography was created in the hope
that it will be a useful resource to the functional programming
community. The site is still in an early stage of development,
and is
At a quick glance,
+5 Awesome.
Cheers
- Tim
On Thu, Jan 14, 2010 at 3:03 PM, James Russell j.russ...@alum.mit.eduwrote:
I am pleased to announce the Functional Programming Bibliography
at http://www.catamorphism.net/
The functional programming bibliography was created in the hope
that it
Oh also, I noticed that you say it's powered by Haskell.
Would you mind sharing some of your architectural details as they relate to
Haskell with us?
On Thu, Jan 14, 2010 at 3:11 PM, Tim Wawrzynczak inforichl...@gmail.comwrote:
At a quick glance,
+5 Awesome.
Cheers
- Tim
On Thu, Jan
Works fine here (Mac OS X 10.5):
MigMit:ngram MigMit$ ghc --make Main.hs srilm.o
[1 of 2] Compiling LM ( LM.hs, LM.o )
LM.hs:9:0: Warning: possible missing in foreign import of FunPtr
[2 of 2] Compiling Main ( Main.hs, Main.o )
Linking Main ...
MigMit:ngram MigMit$ ls
James Russell wrote:
I am pleased to announce the Functional Programming Bibliography
at http://www.catamorphism.net/
I am eager for suggestions as to how the site could be made more
useful.
As is traditional, my ISP's spam filter ate this email. *sigh*
Anyway, I did a search for Simon
While the month-old Go language makes the top 15?
Methods considered unsound.
hjgtuyl:
Haskell has dropped out of the top 50 at Tiobe [1]; how could this hapen?
Let's start selling mobile phones that can only be programmed in Haskell
:-)
[1]
Am Donnerstag 14 Januar 2010 22:19:08 schrieb Miguel Mitrofanov:
Works fine here (Mac OS X 10.5):
MigMit:ngram MigMit$ ghc --make Main.hs srilm.o
[1 of 2] Compiling LM ( LM.hs, LM.o )
LM.hs:9:0: Warning: possible missing in foreign import of FunPtr
[2 of 2] Compiling Main
Hi,
I just updated to GHC 6.12.1, and I noticed a significant drop in I/O
performance that I can't explain. The following code is a simple
re-implementation of cat(1), i.e. it just echos all data from standard
input to standard output:
module Main ( main ) where
import System.IO
import
On Jan 14, 2010, at 17:30 , Peter Simons wrote:
I just updated to GHC 6.12.1, and I noticed a significant drop in I/O
performance that I can't explain. The following code is a simple
re-implementation of cat(1), i.e. it just echos all data from standard
input to standard output:
GHC 6.12.1
On Thu, Jan 14, 2010 at 2:30 PM, Peter Simons sim...@cryp.to wrote:
I just updated to GHC 6.12.1, and I noticed a significant drop in I/O
performance that I can't explain.
This is probably brought about by the new Unicode I/O support in 6.12. Your
file isn't open in binary mode, so it's
Hi List,
Is it possible to prevent a library from being used unless -threaded is
enabled? I have a specific case where lots-of-nasty shows up if the library
is linked against an executable built without -threaded.
I suppose this is GHC specific.
/jve
On Thu, Jan 14, 2010 at 11:38 PM, Bryan O'Sullivan b...@serpentine.com wrote:
On Thu, Jan 14, 2010 at 2:30 PM, Peter Simons sim...@cryp.to wrote:
I just updated to GHC 6.12.1, and I noticed a significant drop in I/O
performance that I can't explain.
This is probably brought about by the new
On Thu, Jan 14, 2010 at 11:21 PM, Don Stewart d...@galois.com wrote:
While the month-old Go language makes the top 15?
Methods considered unsound.
I fully agree. But anyway, I don't think people either already in the
haskell world or about to enter it will find this relevant.
--
Alp Mestan
Hi Svein,
Hold on, he's using hGetBuf/hPutBuf.
exactly, that's what I was thinking. When a program requests that 'n'
bytes ought to be read into memory at the location designated by the
given 'Ptr Word8', how could GHC possibly do any encoding or decoding?
That API doesn't allow for multi-byte
Hello Café,
Symbol tables are a very common data structure in compilers but the most common
implementation uses a hash table as a global variable which results in a space
leak. If we decide to use several symbol tables we still cannot join different
symbol tables.
After some Googling I found
Hi,
are there any IDL compilers that can create Haskelk modules from header
files or type-libs?
Günther
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Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
On Thu, Jan 14, 2010 at 4:12 PM, Tim Wawrzynczak inforichl...@gmail.com wrote:
Oh also, I noticed that you say it's powered by Haskell.
Would you mind sharing some of your architectural details as they relate to
Haskell with us?
Not much to it, really. It's a LAMH thing, if you will.
The
gue.schmidt:
Hi,
are there any IDL compilers that can create Haskelk modules from header
files or type-libs?
The venerable hdirect. http://www.haskell.org/hdirect/
I've recently cabalized the package, which is still in fine condition.
Let me know if you need a copy.
-- Don
Hi Don,
Am 15.01.10 02:00, schrieb Don Stewart:
gue.schmidt:
Hi,
are there any IDL compilers that can create Haskelk modules from header
files or type-libs?
The venerable hdirect. http://www.haskell.org/hdirect/
I've recently cabalized the package, which is still in fine
On Jan 15, 2010, at 3:38 AM, Ian675 wrote:
Pretty much yeah.. Im going through the book and things like :
Define a function rangeProduct which when given natural numbers m
and n,
returns the product m*(m+1)**(n-1)*n
Case analysis and recursion.
If m n, the answer is 1 (the product
Thank you very much Stephen ... I'll try and work on the doc plus the code
you've sent to understand it.
If you do find the parser combinators, please do send it to me.
Thanks and Regards,
Kashyap
- Original Message
From: Stephen Tetley stephen.tet...@gmail.com
Cc:
Hi
Just started an open source project called Hoodoo. It is meant to be a
Lite IDE for Haskell. I wrote it to learn Haskell, so if you are a
beginner (like me) it might interest you. If you're interested follow
this link (http://hoodoo.kenai.com/), and if you like what you see, grab
the code
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